Firstly, there is debate as to whether the T-Rex was a warm or cold blooded animal. Oxygen isotope ratios in fossilised bones have been used to determine the temperature at which the bone was deposited, since the ratio between certain isotopes correlates with temperature. In some cases it was found that the temperature between different parts of the skeleton was very minimal, which led paleontologist, Reese Barrick and geochemist, William Showers, to claim that the T-Rex maintained a constant body temperature. However, others claim that the temperature could have changed during fossilisation. In any case, the signs of homeothermy does not necessarily indicate that the T-Rex was warm-blooded, rather the thermoregulation could be explained as gigantothermy, such as is seen in some living sea turtles.

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Secondly, the T-Rex was a very fast animal. Although there are no marks showing the patterns of the T-Rex running, it has been estimated by scientists that, owing to the large leg muscles, they could run at speeds of between 40 and 70 kilmometres per hour. A study in 2019, also, hypothesised that the `T-Rex was capable of making relatively quick turns and it was likely it could pivot its body more quickly when near to prey, or possibly pirouette on one leg when attacking prey.

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Thirdly, the T-Rex had great sensual ability. By applying modified perimetry to facial reconstructions, a study found that the T-Rex had a binocular eye range of 55 degrees, surpassing that of modern hawks. Furthermore, the study estimated that the T-Rex had 13 times the visual acuity of a human, enabling it to discern a figure 3.7 miles away, compared with a human that can only do so up to a mile away.

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The T-Rex further had very large olfactory bulbs and olfactory nerves in comparison to their brain size. These were the organs responsible for a heightened sense of smell, which therefore suggests that their sense of smell was highly developed and that they would have had the capability to smell carcasses even a long distances away.

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The T-Rex also had an unusually long cochlea, which was often related to hearing acuity and the importance of hearting in social behaviour. We can deduce, therefore, that hearing was an important sense to the T-Rex. On top of this, a study in 2017 found that the snout of tyrannosaurids was highly sensitive, which was deduced from the high number of small openings in the facial bones of the the related species, the Daspletosaurus, which contained sensory neurons. This evidence was taken to hypothesise that the tyrannosaurs might have used their sensitive snouts to gage the temperature of their nests and softly pick up eggs or hatchlings.

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Fourthly, it is generally accepted by most paleontologists that the T-Rex was both an active predator and a scavenger. As the largest carnivore, it was most probably an apex-predator, preying on a range of dinosaurs. Its enormous bite force would have enabled it to crush bones through repetitive biting and thus be able to fully consume the carcasses of large dinosaurs.

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There is, however, debate about whether the T-Rex was exclusively a scavenger rather than an active predator. Palaeontologist, Jack Horner, has argued in favour of the view that the T-Rex was exclusively a scavenger, pointing towards evidence such as its short front of limbs which would have prevented it grappling onto prey, the evidence only showing it walking, its ability to crush bones and thus find nutrition from carcasses and its heightened sense of smell to locate the carcasses.

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Conversely, the reason that natural selection favoured binocular vision would point towards the T-Rex being an active predator. A skeleton of a hadrosaur has, furthermore, been found in Montana, showing healed bite marks from a tyrannosaur. Similarly, on the skeleton of the T-Rex “Sue”, damage marks have been found, which points towards aggressive behaviour.

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Fifthly, there is debate about whether the T-Rex hunted in packs or alone. One piece of evidence found are fossilised trackways from the upper Cretaceous Wapiti Formation of northeastern British Columbia, in Canada, which indicate three tyrannosaurids travelling in the same direction. However, it is an ongoing debate among contemporary scientists.